package com.thomas.netty.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Date;
import java.util.Iterator;
import java.util.Set;

/**   
* @Description: TODO(用一句话描述该文件做什么) 
* @author thomas_liu  
* @date 2018年6月18日 下午10:45:37 
* @version V1.0   
*/
public class MultiplexerTimeServer  implements Runnable {
	
	private Selector selector;
	
	private ServerSocketChannel servChannel;
	
	private volatile boolean stop;

	/**
     * 初始化多路复用器、绑定监听端口
	 * 
     * @param port
	 */
	public MultiplexerTimeServer(int port) {
		
		try {
			selector = selector.open();
			servChannel = ServerSocketChannel.open();
			servChannel.configureBlocking(false);
			servChannel.socket().bind(new InetSocketAddress(port), 1024);
			servChannel.register(selector, SelectionKey.OP_ACCEPT);
			System.out.println("The time server is start in port:"+port);
			
	} catch (IOException e) {
			e.printStackTrace();
			System.exit(1);
		}
	}
	
    public void stop() {
		this.stop = true;
	}

    /*
     * (non-Javadoc)
     * 
	 * @see java.lang.Runnable#run()
	 */
	@Override
	public void run() {
		while(!stop) {
			try {
				selector.select(1000);
				Set<SelectionKey> selectedKeys = selector.selectedKeys();
				Iterator<SelectionKey> it = selectedKeys.iterator();
				SelectionKey key = null;
				while(it.hasNext()){
					key = it.next();
					it.remove();
					
					try {
						handleInput(key);
					} catch (Exception e) {
						if(key != null){
							key.cancel();
			    if (key.channel() != null)
								key.channel().close();
							}
						}
					}
					
				
			} catch (Throwable t) {
				t.printStackTrace();
			}
		}
		
	// 多路复用器关闭后，所有注册在上面的Channel和Pipe等资源都会被自动去注册并关闭，所以不需要重复释放资源
	if (selector != null)
			try {
				selector.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		
	
	private void handleInput(SelectionKey key) throws IOException{
		
		if(key.isValid()){
			
			//处理新接入的请求消息
			if(key.isAcceptable()){
				//Accept the new connection
				ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
				SocketChannel sc = ssc.accept();
				sc.configureBlocking(false);
				//Add the new connection to the selector
				sc.register(selector, SelectionKey.OP_READ);
			}
			if(key.isReadable()){
				//Read the data
				SocketChannel sc = (SocketChannel) key.channel();
				ByteBuffer readBuffer = ByteBuffer.allocate(1024);
				int readBytes = sc.read(readBuffer);
				
				if(readBytes >0){
					readBuffer.flip();
					byte[] bytes = new byte[readBuffer.remaining()];
					readBuffer.get(bytes);
					String body = new String(bytes, "UTF-8");
					System.out.println("The time server receive order :"+body);
					
					String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body)? new Date(System.currentTimeMillis()).toString():"BAD ORDER";
					
					doWrite(sc, currentTime);
					
				}else if(readBytes <0){
					//对端链路关闭
					key.cancel();
					sc.close();
				}else
					;//读到0字节，忽略
			}
		}
	}
	
    private void doWrite(SocketChannel channel, String response)
	    throws IOException {
		if(response != null && response.trim().length()>0){
			byte[] bytes = response.getBytes();
			ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
			writeBuffer.put(bytes);
			writeBuffer.flip();
			channel.write(writeBuffer);
		}
		
	}
	
	
}
